Fish stocks and their prey may respond directly to climate change. For example, physical variables such as sea temperature directly affect the reproduction, growth and mortality of fish stocks. In addition, spatial distributions of fish within the water column and timing of life-history events (such as spawning) might also alter as they adjust geographically to their optimum temperature zone.
Irish waters host vital spawning grounds of several commercial fish species with some species that are found here are at the limit of their geographical distribution, and hence, could be indicator species of climate change. Data collected in the framework of Irish national surveys are crucial to the study of geographical shifts of fish species.
We’re interested in identifying whether or not there are any detectable signals within fisheries data (such as long-term changes in species abundance and/or spatial distribution, or fluctuations in reproduction and/or condition) that can be attributable to climate change. Possible oceanographic changes (in salinity or current strengths for example) that may trigger ecosystem or migratory changes will be particularly relevant.
A further intricacy is that climate change and fisheries exploitation may vary so that it is hard to attribute change to one or the other process. This interaction is poorly understood and the scientific community must address this complex issue if we are to develop realistic predictions of the likely impact of climate warming on fisheries that are so important to our nation and Europe. A way forward will be to build a model of the ecosystem so that we can evaluate possible future scenarios given our knowledge of both climate change and human activities.